Chincha Islands War

The Chincha Islands War occurred from 1864 to 1866 between the Kingdom of Spain and the South American countries of Peru and Chile, soon joined by Ecuador and Bolivia. The conflict was largely seen as an attempt by Queen Isabella II of Spain to reassert Spanish authority over the former colonies of the Spanish Empire in South America. The Spanish-South American War began when Spain occupied some islands off the Peruvian-Chilean coast and was notable for the early usage of ironclad warships.

Background
During the reign of Queen Isabella II, Spain greatly increased its military spending and the Spanish Navy rose to be world's fourth biggest navy. The kingdom engaged in wars in the Philippines, Morocco, and Mexico. In late 1862, the Spanish government sent a fleet of ships to the South American Pacific coast, visiting Peru and Chile. Ostensibly, it was a research mission, but they were really there to defend the interests and rights of Spanish citizens in those countries. The outbreak of violence in August 1863 in a Peruvian town that led to the death of a Spaniard prompted the fleet to visit Peru and demand compensation. They also demanded money for the losses during the Peruvian War of Independence. Peru refused, but the government in Madrid sent an envoy to negotiate. The envoy had the title of commissioner—that of a colonial administrator rather than a proper ambassador.

The War
In April 1863 the Spanish fleet of ironclad ships seized the Chincha Islands, which included some of Peru's guano resources and produced 60% of government revenue. They also blockaded the Peruvian coast, interrupting trade and commerce. A treaty negotiated between Spanish admiral Juan Manuel Pareja and the representative of Peruvian president Juan Antonio Pezet was signed on 27 January 1865, but it was viewed as an insult to Peruvian honor and Pezet's government soon fell.

Other South American countries, including Chile, believed this was an attempt by Spain to recreate its colonial empire in the Americas. When a Spanish gunboat stopped for coal at a Chilean port, it was refused by the Chilean government, which proclaimed neutrality. Upon hearing of this, Admiral Pareja sent four warships, whose commander demanded that the Chileans greet them with a 21-gun salute. This was refused and war was declared in September 1865.